1. Field of the Invention
The invention relates to a plasma wire burner for plasma spray having at least two burner tubes for supplying electrodes which are in the form of wires and are passed through the burner tube in the direction of the surface of an object to be coated via a feed device which has numerous guiding and/or sliding elements which are mounted such that they can rotate.
2. Related Art of the Invention
Plasma wire burners having a variant large number of guiding means for the spray wire are already known in a general form. JP 01 198 461 A, JP 02 245 255 A, JP 02 307 555 A, JP 05 168 985 A and JP 07 090 537 A should be cited by way of example.
An inner burner for plasma wire spraying of cavities, in particular of cylindrical running surfaces, is already known (DE 198 41 617 A1). The inner burner has two burner tubes which are provided for feeding wire electrodes. The electrodes are melted by means of a plasma. Furthermore, the inner burner has a gas supply for a process gas, which is provided for transportation and atomization of the molten wire material in the direction of that surface of the cavity which is to be coated. The electrodes or the wires are fed towards one another through the burner tubes on the outlet side and in the area of the plasma, with the plasma from the electrode wires, which is arranged in the contact area of the wires, being arranged in the area of the gas flow of the emerging process gas. The gas flow of the emerging process gas, which is referred to for simplicity in the following text as the main gas flow direction, is arranged transversely with respect to the main transportation direction of the wires, which is governed by the burner tubes. Layers which are sprayed by means of an inner burner such as this onto, in particular, a metallic substrate, preferably a cylindrical running surface, are generally highly porous.
A welding burner with a feed apparatus for electrodes in the form of wire is known from JP-11 342471, which electrodes are passed through the burner tube via rollers which are mounted such that they can rotate, in the direction of that surface of an object which is to be coated, with the feed device being provided outside the welding burner.